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Node-RED with WS2812B Addressable RGB LED Strip

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Addressable RGB LED strips are just awesome! You can control each individual pixel of the strip, allowing you to produce beautiful effects. However, controlling these kind of strips it’s not always easy. So, in this project we’re going to show you how to build a web application with Node-RED and Raspberry Pi to control an addressable RGB LED strip to make your life simple.

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Wiring the WS2812B RGB LED Strip

With your Pi shutdown, follow the next schematic diagram to wire the WS2812B RGB LED strip to your Pi. The WS2812B data pin should be controlled by the Pi’s GPIO17, because that’s the GPIO used by the neopixel node.

Installing the neopixel Node-RED node

To control the WS2812B addressable RGB LED strip with Node-RED, first you need to install node-red-pi-neopixel. First, you need to install the Neopixel python driver. So, in the Terminal window type the following (this may take a few minutes):

Starting Node-RED

To access Node-RED, open a tab in any browser on the local network and type the following:

http://Your_RPi_IP_address:1880

You should replace Your_RPi_IP_address with your Raspberry Pi IP address. If you don’t know your Raspberry Pi IP address, in the Terminal enter:

pi@raspberry:~ $ hostname -I

Creating the Node-RED Flow

Before creating the flow, make sure you have the rpi neopixels node, as show in the figure below. If you don’t have the node, check that you’ve followed the instructions above in the Installing the neopixel Node-RED node section.

Here’s the flow to control the WS2812B RGB LED strip.

As this flow is a bit complex, we recommend importing the flow we provide instead of building it from scratch. Then, you can make modifications to the flow, if necessary.

Importing the Node-RED flow

To import the Node-RED flow provided, go to the GitHub repository or click the figure below to see the raw file, and copy the code provided.

Next, in the Node-RED window, at the top right corner, select the menu, and go to Import > Clipboard.

Then, paste the code provided and click Import.

Select the Number of LEDs

This flow was built for a strip with 14 LEDs. You’ll be probably using a different number of LEDs. So, you’ll need to make some changes to the flow.

WS2812B LED STRIP Node

Double click the WS2812B LED STRIP node, and change the number of LEDs in the first field.

Select LED Slider Node

You also should edit the Select LED Slider Node, so that you are able to select all the pixels on your strip with the slider.

Select LED Numeric Node

You need to edit the Select LED numeric node to match the number of LEDs on your strip.

Rainbow Effect Function Node

Edit the number of LEDs on the Rainbow Effect function node, as highlighted in the figure below. You need to do this, so that the rainbow effect spreads across the number of LEDs on your strip.

Adding More Preset Colors

This Node-RED application has a drop-down menu that allows to chose a color for the entire strip. We’ve added some preset colors, but you can add more colors if you like. For that, double-click on the Select Strip Color drop-down node and add more options. You should set the color in RGB.

Node-RED UI

After making all the necessary changes, click the Deploy button to save all the changes.

Now, you Node-RED application is ready. To access Node-RED UI and see how your application looks, access any browser in your local networks and type:

http://Your_RPi_IP_address:1880/ui

Your application should look as in the following figure.

Wrapping up

In this project we’ve made a Node-RED application to control the WS2812B RGB LED strip using the neopixel node. We hope you’ve liked this project, and have fun controlling your LED strip.